debian: Drop debian/compat

Less downstream diff noise

Gbp-Dch: Ignore
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

debian/compat

-12

debian/control

@@ -3,7 +3,7 @@ Section: x11
 Priority: optional
 Maintainer: Guido Günther <agx@sigxcpu.org>
 Build-Depends:
- debhelper (>= 12),
+ debhelper-compat (= 12),
  gtk-doc-tools <!nodoc>,
  libsecret-1-dev,
  libsystemd-dev,